"It was intimate -- just 16 people," a source tells the new issue of Us Weekly (on stands now).

At the lavender-themed bash, guests sipped purple Hpnotiq Harmonie cocktails in a garden decorated with violets. Attendees also hammed it up with a feather boa in a photo booth, wrote notes to the bride-to-be in a scrapbook and then sat down for dinner.

The actress, 30, is clearly ecstatic to walk down the aisle. "I heard her trying out 'Vanessa Minnillo Lachey,'" adds the source. And Minnillo tells Us she already knows the best part of marriage: "It's transitioning into becoming a family."